secure latches . This in turn is connected to a familiar-looking handset . Incorporting the tried and trusted Shearwater Petrel computer into the system gave me instant confidence in the unit , while no doubt also saving Hollis a small fortune in development costs .
Attached to the DSV ( Dive Surface Valve ) mouthpiece , there is also a colour-coded HUD ( Heads Up Display ) to monitor the three oxygen sensors located in the head of the unit . I liked the fact that there was also a red warning light located on the extremety of the HUD , which could alert my buddy to any problem .
Pre-flight checks
If a checklist is a pre-flight essential for an airline pilot , it ’ s good enough for a Prism II diver . Scott and I carried out the manufacturer ’ s recommended checks before pre-breathing our units prior to diving .
The Prism uses a stainless steel backplate , a continuous harness , crotch strap and a wing for buoyancy . That ’ s a pretty standard setup for many divers , and one which they should feel comfortable using . It also features a small stainless steel stand , which I found an advantage during the process of kitting-up or setting down the unit .
I required just a little extra lead to achieve correct weighting , however there were still enough differences in switching from my usual CCR to an unfamiliar one and this did affect my initial buoyancy control .
Contending with both my camera and a 7-litre bailout cylinder also contributed to a slightly lop-sided feel to my experience , but after a few minutes of acclimatising I could begin to enjoy myself a little more .
While the unit can be ‘ driven ’ in what amounts to fully automatic mode ( diluent added when required ), there are also input valves for diluent and oxygen , should manual control or loop flushing be required .
Hollis claims that the Prism II has the lowest WOB ( Work of Breathing ) in the industry , and while I ’ d need an ANSTI machine to confirm that , I was more than satisfied with its performance ; it compared favourably with what I ’ m used to .
It ’ s very difficult to fully assess any CCR ’ s true capabilities in the short duration and shallow depth of a one-off try-dive , but I did experience enough of the Prism II to want to explore the unit more comprehensively in the future .
If I ’ d not already invested heavily in my current CCR or was looking to take my first steps into the rebreather world then I ’ d certainly consider the Prism II as a suitable candidate for the move . Neil Hope
Above : Pre-breathing the Prism II Below : Contents gauge and manual gas control
SCUBA SAYS
The Hollis Prism II has been a long time coming to our shores , but initial impressions are that this compact unit is competitively-priced , welldesigned , simple to assemble / disassemble and its Shearwater tiein ensures reliable and easy-to-use electronic monitoring .
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